/*
 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch_helpers.h>
#include <assert.h>
#include <bl_common.h>
#include <debug.h>
#include <delay_timer.h>
#include <generic_delay_timer.h>
#include <platform.h>

/* Ticks elapsed in one second by a signal of 1 MHz */
#define MHZ_TICKS_PER_SEC 1000000

static timer_ops_t ops;

static uint32_t get_timer_value(void)
{
    /*
     * Generic delay timer implementation expects the timer to be a down
     * counter. We apply bitwise NOT operator to the tick values returned
     * by read_cntpct_el0() to simulate the down counter. The value is
     * clipped from 64 to 32 bits.
     */
    return (uint32_t)(~read_cntpct_el0());
}

void generic_delay_timer_init_args(uint32_t mult, uint32_t div)
{
    ops.get_timer_value    = get_timer_value;
    ops.clk_mult        = mult;
    ops.clk_div        = div;

    timer_init(&ops);

    VERBOSE("Generic delay timer configured with mult=%u and div=%u\n",
        mult, div);
}

void generic_delay_timer_init(void)
{
    /* Value in ticks */
    unsigned int mult = MHZ_TICKS_PER_SEC;

    /* Value in ticks per second (Hz) */
    unsigned int div  = plat_get_syscnt_freq2();

    /* Reduce multiplier and divider by dividing them repeatedly by 10 */
    while ((mult % 10 == 0) && (div % 10 == 0)) {
        mult /= 10;
        div /= 10;
    }

    generic_delay_timer_init_args(mult, div);
}

